Poising tool for watchmakers



March 3, 1942. Jfl. HANSEN 2,275,144

POISING TOOL FOR WATCHMAKERS Filed April 5, 1940 .NVENTQR J95 44 554 W ATTORNEY Patented Mar. 3, 1942 UNITED STAT E S PAT i i '3 OFFICE 1 Claim.

This invention relates to a tool for watchmakers and more particularly to a tool .for poising and aligning balance wheels. The principal object is to provide a simple, neat, and efficient whereby the alignment of the balance wheel and staff can be easily checked.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efliciency. These will become more apparent from the following description.

In the following detailed description of the invention reference is had to the accompanying drawing which forms a pan; thereof. Like numerals refer to like parts in all views of the drawing and. throughout the description.

In the drawing:

Fig. 1 is a perspective view of the improved watchmakers tool as it would appear in use.

Fig. 2 is a top plan view with a magnifying glass in place thereon.

Fig. 3 is a detailed enlarged view illustrating the extremities of the jeweled bearing bars with a balance wheel in place therein, and with a pivot straightening screw in place therein.

Fig. 4 is a front view of the improved tool.

Figs. 5 and 6 are detail, perspective views of the jeweled bearing bars.

Fig. 7 is a detail view of a type of vibrating tool which may be employed with this invention.

Fig. 8 is a side sectional view, taken on the line 88, Fig. 2.

Fig. 9 is an enlarged sectional view illustrating the position and construction of a pivot straightening screw which may be employed with the invention.

For the purpose of illustration, a typical watch balance wheel is illustrated at 31, with its staff at 38, and its staff pivots at 36.

The improved watchmakers tool consists of a frame plate It], terminating at its rearward extremity in two bench engaging legs H and at its forward extremity in two clamping arms l2. A finger hole I3 is formed through the midportion of the frame [8 in which the operator's finger is pressed to hold the tool stationary on the bench while in use.

The forward extremity of the frame plate In is supported on two knurled legs 14 which are held in place by means of threaded extremities 15. The arms i? are split, as shown at M5, on a plane parallel with and intermediate of the surfaces of the plate iii. The threaded extremities of the legs are threaded into the plate I 0 in that portion above the split it so that when they are screwed tightly into place, they will act to contact the splits IS. The legs serve the double purpose of supporting the plate l0 and clamping the splits.

The arms l2 are drilled in alignment with each other through the splits I6 to receive two jeweled bearing bars I! and H3. The bearing bars I! and i8 are formed with knurled heads l9 at their outer extremities and, when the legs I4 are loosened, they may be slid freely through the arms 52. The inner extremities of both arms are provided with notches 2!} extending slightly more than onehalf the way through the bars. These notches are placed sufficiently close to the ends of the bar to leave a relatively thin jewel plate 2| thereon.

In each jewel plate a standard balance wheel pivot jewel is mounted. The bar I! carries a full complete jewel 22. The bar l8 carries onehalf of a complete jewel 23. The half jewel is formed by finishing the bar 18 exactly similar to the bar" and then cutting the jewel plate 2| and the jewel diametrically in half.

Some of the tools have been manufactured in which both jewels are cut in half similar to the one shown in Fig. 5. This facilitates the placement of the balance staff pivots thereon but such a construction does not hold the pivots as securely against displacement as a construction in which one of the jewels remains complete.

In use the bearing bars I! and I8 are adjusted in the plate ID to the length of the balance staff 38 of the wheel 3'! to be poised. The bars are then clamped in their adjusted positions by tightening the legs M. The tool is then placed on the watchmakers bench and held by placing the forefinger of the one hand in the opening 13 to hold the tool against the bench, while the balance staff pivots 36 are inserted in the jewels with the other hand.

The pivot at one extremity of the balance staff is first inserted in the complete jewel 22 and the other pivot is dropped into the half jewel 23. The device is then vibrated to cause the heavy side, if any, of the balance Wheel to gravitate to the bottom. This vibration may be accomplished by means of a knurled vibrating tool 24, as shown in Fig. 7. The knurled portion of this tool is drawn across the projecting portions of the bars Hand l8 to vibrate the wheel.

To facilitate observation of the wheel and its pivots, a magnifying lens 25 may be provided, mounted in a suitable frame 28 from which a supporting arm 2'! extends to a friction clamp member 23. The friction clamp is slidably mounted on a post 29. The post passes through an opening in the plate Hi and may be locked in any desired position therein by means of a knurled set screw 30.

The lens 25 may be provided with an index line 3| which by swinging the lens may be brought into alignment with the plane or the balance wheel. By rotating the wheel and comparing it with this line it can be quickly determined whether the wheel is true with its shaft pivots.

A second index line 32 crossing the first line at right angles can be brought into alignment with the axes of the two bearing jewels to determine, by the wabble of the staff, the straightness of the staff pivots.

A pivot straightening screw 33 may be threaded through the bottom of the slot 28 in the bearing bar ll. The extremity of this screw is cupped as indicated at St to provide a raised, rounded, peripheral edge 35 one side of which contacts the staif pivot 3%; of the balance wheel. A knurled head 37 is formed on the screw 33 by means of which it may be rotated to bring pressure against the staff pivot 36 for straightening the latter. It will be noted that the raised edge 35 is rounded so that it will contact the pivot at a single point for accurate straightening effect.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same may be varied, within the scope of the appended claim, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is:

A watchmakers poising tool comprising: a frame plate; arms projecting from said frame plate; a bearing bar in each arm, said bars being directed toward, and in alignment, with each other; means for supporting a balance stafi between the adjacent extremities of the bars, the adjacent extremities of the bearing bars being transversely notched to a depth exceeding onehalf of their diameters; jewel retaining portions on said bars between the extremities and said notches; a jewel mounted in the retaining portion of each bar for receiving the pivot of a balance staff; and a pivot straightening screw threaded through the bottom of the transverse notch in one of said bearing bars to contact the staff pivot positioned in the jewel of said bar when desired.

JES I. HANSEN. 

